This invention relates generally to dishwashers, and more particularly, to methods and apparatus for filling a dishwasher.
Reducing the amount of energy consumption by a fluid-handling dishwasher for cleansing articles is a significant problem, in part because of increasing worldwide energy demand. In such dishwashers, the amount of energy consumed is primarily determined by the amount of energy needed to heat the liquid, such as water, used to cleanse the articles. Thus, decreased liquid consumption for such dishwashers can result in a significant improvement in energy efficiency.
Dishwashers typically receive liquid for a predetermined duration through a conduit connected to the dishwasher. A wash cycle for a dishwasher for cleansing articles may include providing substantially particle-free liquid to the dishwasher, circulating or distributing the liquid during the wash cycle, and draining or flushing the liquid from the dishwasher after being used to wash the articles. Typically, a dishwasher user has limited control over the amount of liquid provided for a wash cycle, such as by selection from a few predetermined options. Such a dishwasher does not use liquid efficiently because variations in liquid pressure or degradation in dishwasher components generally require providing liquid for an excessive duration to ensure a more than sufficient amount for a wash cycle. Closed loop feedback control is one method to improve water conservation in dishwashers. Several devices are available to monitor or measure the amount or volume of liquid provided for a wash cycle.
Devices for measuring the amount of liquid, such as water, provided to a dishwasher for cleansing articles include flowmeters that measure the water flow rate to the dishwasher and water level sensors that detect the static air pressure in an air cavity in the sensor. However, such devices may be difficult or non-economic to implement, may be unreliable, may degrade over time, and may not provide robust measurements relative to the dishwashers incorporating them. Furthermore, the accuracy of such devices is not entirely satisfactory due to variations in the amount of liquid needed to satisfactorily cleanse varying amounts of soiled articles.
A need thus exists for a dishwasher for cleansing articles incorporating a closed loop feedback system for monitoring and controlling the amount of liquid provided for a wash cycle.